Check pointer equality for Eq on Structs

compiler/mono/src/code_gen_help.rs

@@ -360,11 +360,7 @@ impl<'a> CodeGenHelp<'a> {
     /// Generate refcounting helper procs, each specialized to a particular Layout.
     /// For example `List (Result { a: Str, b: Int } Str)` would get its own helper
     /// to update the refcounts on the List, the Result and the strings.
-    pub fn generate_procs(
-        &mut self,
-        arena: &'a Bump,
-        ident_ids: &mut IdentIds,
-    ) -> Vec<'a, Proc<'a>> {
+    pub fn generate_procs(&self, arena: &'a Bump, ident_ids: &mut IdentIds) -> Vec<'a, Proc<'a>> {
         use HelperOp::*;
 
         // Clone the specializations so we can loop over them safely
@@ -407,7 +403,7 @@ impl<'a> CodeGenHelp<'a> {
     /// Only called while generating bodies of helper procs
     /// The list of specializations should be complete by this time
     fn apply_op_to_sub_layout(
-        &mut self,
+        &self,
         op: HelperOp,
         sub_layout: &Layout<'a>,
         arguments: &'a [Symbol],
@@ -468,7 +464,7 @@ impl<'a> CodeGenHelp<'a> {
     // ============================================================================
 
     fn refcount_generic(
-        &mut self,
+        &self,
         ident_ids: &mut IdentIds,
         layout: Layout<'a>,
         op: HelperOp,
@@ -502,7 +498,7 @@ impl<'a> CodeGenHelp<'a> {
     // for the 'pointer' and 'integer' versions of the address.
     // This helps to avoid issues with the backends Symbol->Layout mapping.
     fn rc_ptr_from_struct(
-        &mut self,
+        &self,
         ident_ids: &mut IdentIds,
         structure: Symbol,
         rc_ptr_sym: Symbol,
@@ -562,7 +558,7 @@ impl<'a> CodeGenHelp<'a> {
     }
 
     /// Generate a procedure to modify the reference count of a Str
-    fn refcount_str(&mut self, ident_ids: &mut IdentIds, op: HelperOp) -> Stmt<'a> {
+    fn refcount_str(&self, ident_ids: &mut IdentIds, op: HelperOp) -> Stmt<'a> {
         let string = Symbol::ARG_1;
         let layout_isize = self.layout_isize;
 
@@ -679,11 +675,9 @@ impl<'a> CodeGenHelp<'a> {
     //
     // ============================================================================
 
-    fn eq_generic(&mut self, ident_ids: &mut IdentIds, layout: Layout<'a>) -> Stmt<'a> {
+    fn eq_generic(&self, ident_ids: &mut IdentIds, layout: Layout<'a>) -> Stmt<'a> {
         let eq_todo = || todo!("Specialized `==` operator for `{:?}`", layout);
 
-        let arguments = &[Symbol::ARG_1, Symbol::ARG_2];
-
         let main_body = match layout {
             Layout::Builtin(
                 Builtin::Int(_) | Builtin::Float(_) | Builtin::Bool | Builtin::Decimal,
@@ -695,12 +689,7 @@ impl<'a> CodeGenHelp<'a> {
                 unreachable!("No generated helper proc for `==` on Str. Use Zig function.")
             }
             Layout::Builtin(Builtin::Dict(_, _) | Builtin::Set(_) | Builtin::List(_)) => eq_todo(),
-            Layout::Struct(field_layouts) => self.eq_struct(
-                ident_ids,
-                field_layouts,
-                arguments,
-                Stmt::Ret(Symbol::BOOL_TRUE),
-            ),
+            Layout::Struct(field_layouts) => self.eq_struct(ident_ids, field_layouts),
             Layout::Union(_) => eq_todo(),
             Layout::LambdaSet(_) => unreachable!("`==` is not defined on functions"),
             Layout::RecursivePointer => eq_todo(),
@@ -719,7 +708,64 @@ impl<'a> CodeGenHelp<'a> {
         )
     }
 
-    fn if_false_return_false(&mut self, symbol: Symbol, following: &'a Stmt<'a>) -> Stmt<'a> {
+    fn if_pointers_equal_return_true(
+        &self,
+        ident_ids: &mut IdentIds,
+        ptr1: Symbol,
+        ptr2: Symbol,
+        following: &'a Stmt<'a>,
+    ) -> Stmt<'a> {
+        let ptr1_addr = self.create_symbol(ident_ids, &format!("{:?}_addr", ptr1));
+        let ptr2_addr = self.create_symbol(ident_ids, &format!("{:?}_addr", ptr2));
+        let ptr_eq = self.create_symbol(ident_ids, &format!("eq_{:?}_{:?}", ptr1_addr, ptr2_addr));
+
+        Stmt::Let(
+            ptr1_addr,
+            Expr::Call(Call {
+                call_type: CallType::LowLevel {
+                    op: LowLevel::PtrCast,
+                    update_mode: UpdateModeId::BACKEND_DUMMY,
+                },
+                arguments: self.arena.alloc([ptr1]),
+            }),
+            self.layout_isize,
+            self.arena.alloc(Stmt::Let(
+                ptr2_addr,
+                Expr::Call(Call {
+                    call_type: CallType::LowLevel {
+                        op: LowLevel::PtrCast,
+                        update_mode: UpdateModeId::BACKEND_DUMMY,
+                    },
+                    arguments: self.arena.alloc([ptr2]),
+                }),
+                self.layout_isize,
+                self.arena.alloc(Stmt::Let(
+                    ptr_eq,
+                    Expr::Call(Call {
+                        call_type: CallType::LowLevel {
+                            op: LowLevel::Eq,
+                            update_mode: UpdateModeId::BACKEND_DUMMY,
+                        },
+                        arguments: self.arena.alloc([ptr1_addr, ptr2_addr]),
+                    }),
+                    LAYOUT_BOOL,
+                    self.arena.alloc(Stmt::Switch {
+                        cond_symbol: ptr_eq,
+                        cond_layout: LAYOUT_BOOL,
+                        branches: self.arena.alloc([(
+                            1,
+                            BranchInfo::None,
+                            Stmt::Ret(Symbol::BOOL_TRUE),
+                        )]),
+                        default_branch: (BranchInfo::None, following),
+                        ret_layout: LAYOUT_BOOL,
+                    }),
+                )),
+            )),
+        )
+    }
+
+    fn if_false_return_false(&self, symbol: Symbol, following: &'a Stmt<'a>) -> Stmt<'a> {
         Stmt::Switch {
             cond_symbol: symbol,
             cond_layout: LAYOUT_BOOL,
@@ -731,8 +777,23 @@ impl<'a> CodeGenHelp<'a> {
         }
     }
 
-    fn eq_struct(
-        &mut self,
+    fn eq_struct(&self, ident_ids: &mut IdentIds, field_layouts: &'a [Layout<'a>]) -> Stmt<'a> {
+        let else_clause = self.eq_fields(
+            ident_ids,
+            field_layouts,
+            &[Symbol::ARG_1, Symbol::ARG_2],
+            Stmt::Ret(Symbol::BOOL_TRUE),
+        );
+        self.if_pointers_equal_return_true(
+            ident_ids,
+            Symbol::ARG_1,
+            Symbol::ARG_2,
+            self.arena.alloc(else_clause),
+        )
+    }
+
+    fn eq_fields(
+        &self,
         ident_ids: &mut IdentIds,
         field_layouts: &'a [Layout<'a>],
         arguments: &'a [Symbol],